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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "net/filter/brotli_source_stream.h"
#include "base/bind.h"
#include "base/bit_cast.h"
#include "base/check_op.h"
#include "base/memory/raw_ptr.h"
#include "base/metrics/histogram_macros.h"
#include "net/base/io_buffer.h"
#include "third_party/brotli/include/brotli/decode.h"
namespace net {
namespace {
const char kBrotli[] = "BROTLI";
// BrotliSourceStream applies Brotli content decoding to a data stream.
// Brotli format specification: http://www.ietf.org/id/draft-alakuijala-brotli.
class BrotliSourceStream : public FilterSourceStream {
public:
explicit BrotliSourceStream(std::unique_ptr<SourceStream> upstream)
: FilterSourceStream(SourceStream::TYPE_BROTLI, std::move(upstream)) {
brotli_state_ =
BrotliDecoderCreateInstance(AllocateMemory, FreeMemory, this);
CHECK(brotli_state_);
}
BrotliSourceStream(const BrotliSourceStream&) = delete;
BrotliSourceStream& operator=(const BrotliSourceStream&) = delete;
~BrotliSourceStream() override {
BrotliDecoderErrorCode error_code =
BrotliDecoderGetErrorCode(brotli_state_);
BrotliDecoderDestroyInstance(brotli_state_);
brotli_state_ = nullptr;
DCHECK_EQ(0u, used_memory_);
UMA_HISTOGRAM_ENUMERATION(
"BrotliFilter.Status", static_cast<int>(decoding_status_),
static_cast<int>(DecodingStatus::DECODING_STATUS_COUNT));
if (decoding_status_ == DecodingStatus::DECODING_DONE) {
// CompressionPercent is undefined when there is no output produced.
if (produced_bytes_ != 0) {
UMA_HISTOGRAM_PERCENTAGE(
"BrotliFilter.CompressionPercent",
static_cast<int>((consumed_bytes_ * 100) / produced_bytes_));
}
}
if (error_code < 0) {
UMA_HISTOGRAM_ENUMERATION("BrotliFilter.ErrorCode",
-static_cast<int>(error_code),
1 - BROTLI_LAST_ERROR_CODE);
}
// All code here is for gathering stats, and can be removed when
// BrotliSourceStream is considered stable.
const int kBuckets = 48;
const int64_t kMaxKb = 1 << (kBuckets / 3); // 64MiB in KiB
UMA_HISTOGRAM_CUSTOM_COUNTS("BrotliFilter.UsedMemoryKB",
used_memory_maximum_ / 1024, 1, kMaxKb,
kBuckets);
}
private:
// Reported in UMA and must be kept in sync with the histograms.xml file.
enum class DecodingStatus : int {
DECODING_IN_PROGRESS = 0,
DECODING_DONE,
DECODING_ERROR,
DECODING_STATUS_COUNT
// DECODING_STATUS_COUNT must always be the last element in this enum.
};
// SourceStream implementation
std::string GetTypeAsString() const override { return kBrotli; }
base::expected<size_t, Error> FilterData(
IOBuffer* output_buffer,
size_t output_buffer_size,
IOBuffer* input_buffer,
size_t input_buffer_size,
size_t* consumed_bytes,
bool /*upstream_eof_reached*/) override {
if (decoding_status_ == DecodingStatus::DECODING_DONE) {
*consumed_bytes = input_buffer_size;
return 0;
}
if (decoding_status_ != DecodingStatus::DECODING_IN_PROGRESS)
return base::unexpected(ERR_CONTENT_DECODING_FAILED);
const uint8_t* next_in = base::bit_cast<uint8_t*>(input_buffer->data());
size_t available_in = input_buffer_size;
uint8_t* next_out = base::bit_cast<uint8_t*>(output_buffer->data());
size_t available_out = output_buffer_size;
BrotliDecoderResult result =
BrotliDecoderDecompressStream(brotli_state_, &available_in, &next_in,
&available_out, &next_out, nullptr);
size_t bytes_used = input_buffer_size - available_in;
size_t bytes_written = output_buffer_size - available_out;
CHECK_GE(input_buffer_size, available_in);
CHECK_GE(output_buffer_size, available_out);
produced_bytes_ += bytes_written;
consumed_bytes_ += bytes_used;
*consumed_bytes = bytes_used;
switch (result) {
case BROTLI_DECODER_RESULT_NEEDS_MORE_OUTPUT:
return bytes_written;
case BROTLI_DECODER_RESULT_SUCCESS:
decoding_status_ = DecodingStatus::DECODING_DONE;
// Consume remaining bytes to avoid DCHECK in FilterSourceStream.
// See crbug.com/659311.
*consumed_bytes = input_buffer_size;
return bytes_written;
case BROTLI_DECODER_RESULT_NEEDS_MORE_INPUT:
// Decompress needs more input has consumed all existing input.
DCHECK_EQ(*consumed_bytes, input_buffer_size);
decoding_status_ = DecodingStatus::DECODING_IN_PROGRESS;
return bytes_written;
// If the decompressor threw an error, fail synchronously.
default:
decoding_status_ = DecodingStatus::DECODING_ERROR;
return base::unexpected(ERR_CONTENT_DECODING_FAILED);
}
}
static void* AllocateMemory(void* opaque, size_t size) {
BrotliSourceStream* filter = reinterpret_cast<BrotliSourceStream*>(opaque);
return filter->AllocateMemoryInternal(size);
}
static void FreeMemory(void* opaque, void* address) {
BrotliSourceStream* filter = reinterpret_cast<BrotliSourceStream*>(opaque);
filter->FreeMemoryInternal(address);
}
void* AllocateMemoryInternal(size_t size) {
size_t* array = reinterpret_cast<size_t*>(malloc(size + sizeof(size_t)));
if (!array)
return nullptr;
used_memory_ += size;
if (used_memory_maximum_ < used_memory_)
used_memory_maximum_ = used_memory_;
array[0] = size;
return &array[1];
}
void FreeMemoryInternal(void* address) {
if (!address)
return;
size_t* array = reinterpret_cast<size_t*>(address);
used_memory_ -= array[-1];
free(&array[-1]);
}
raw_ptr<BrotliDecoderState> brotli_state_;
DecodingStatus decoding_status_ = DecodingStatus::DECODING_IN_PROGRESS;
size_t used_memory_ = 0;
size_t used_memory_maximum_ = 0;
size_t consumed_bytes_ = 0;
size_t produced_bytes_ = 0;
};
} // namespace
std::unique_ptr<FilterSourceStream> CreateBrotliSourceStream(
std::unique_ptr<SourceStream> previous) {
return std::make_unique<BrotliSourceStream>(std::move(previous));
}
} // namespace net
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